The structural system provides a framework for the body. Consisting of bones, muscles and connective tissues, it gives the body not only form, but also the ability to move. It also houses all the other body systems, protecting them from the outside environment. When a baby is born, it has about 350 bones, all soft because they are composed mostly of a water substance called cartilage. As the baby grows, calcium phosphate permeates the bones, and they stiffen. This process is called calcification. Eventually calcified cartilage is replaced by true bone, made up largely of calcium phostate, and some of the bones fuse together. A normal adult has between 206 and 209 bones in his body, depending upon whether he has one or two additional ribs and an extra bone in the coccyx (tailbone). Calcium phosphate is deposited in bones in two ways. At the outer edge it takes the form of a solid, compact material covered by a membrane called the periosteum. Deeper inside, it becomes a honeycomb of sponge-like, porous material called cancellous bone. A soft material known as marrow fills the spaces inside the cancellous bone. Marrow is actually the manufacturing site of both red and white blood cells, and as such is tunneled with vessels that move freshly made red and white blood cells out and bring in red ones containing essential nutrients. Although bones generally stop growing in length during mid-teens for girls and at around age 20 for boys, they never really stop the growing process, because they are constantly rebuilding themselves. Bones contain two types of cells, osteoblasts and osteoclasts. These work together to continually build new bone material on the outside and remove old, unneeded material from the inside. To sustain this growth, the body must have sufficient supplies of certain nutrients including calcium, phosphorus and vitamin D. If there is a shortage of calcium in the bloodstream, the body will remove it from the bones without replacing it. This can eventually cause bones to become weak and porous. Unchecked, it can lead to a severely lifestyle-limiting, sometimes fatal condition known as osteoporosis.

Connections Joints have been called masterpieces of engineering because they are designed to permit movement between bones that must meet, but not touch each other. Their role is to bind two or more bones firmly together while cushioning and lubricating them well enough to last through a lifetime of lifting, swinging, bending, walking, etc. While their individual construction may vary, most joints are made up of the same elements. The joint is enclosed in a tough, fibrous capsule of connective tissue that secretes a liquid called synovial fluid. The synovial fluid lubricates the moving parts. Outside the capsule, fibrous anchors called ligaments surround the joint and link the bones. Ligaments protect the capsule and help keep all motion of the joint within safe limits. In places where muscle tissues, called tendons or sinews, pass next to large joints so that muscles on one side will be linked to bones on the other, small fluid-filled pouches, or bursae, also act as buffers.Muscles Bones and sinews may control the movement of the body, but muscles create them by converting chemical energy from food into mechanical energy. Muscles perform their work by contracting. This means that they pull, never push, and because of this it takes a pair of them to make a range of movement possible. There are move than 600 muscles in the body consisting of three basic types: heart muscle, smooth muscle, and skeletal muscle. Each muscle is made up of innumerable tiny, sting-like fibers, and each of these, in turn, is composed of bundles of infinitesimal filaments varying in length from half an inch to about a foot. Small muscles have just a few fibers, while large ones have a great many. Muscles grow strong through use. The effort it takes to use muscles make the heart supply them with more blood and nutrients. This stimulates the growth of new muscle fibers and blood vessels. In effect, exercise enlarges and strengthens muscles just as it does bones.

Factors in structural health Regular, lifelong activity is essential to keeping bones and muscles functioning optimally. If a person is never very active, his/her bones won't be able to grow as dense as nature meant them to be. Likewise, if a person is active enough to develop the stongest skeleton possible, but then becomes inactive, the bone that is no longer needed will eventually be lost. Diet is also extremely important. As mentioned earlier, a shortage of calcium over an extended period of time can spell disaster. In fact, the loss of calcium is the most serious nutritional problem experienced by older Americans. Bone loss appears to begin as early as age 35, and is particularly serious for women. As they approach menopause, their rate of bones loss accelerates greatly, partly because of a decreased secretion of the hormone estrogen, which helps maintain bone mass. An estimated 5 million women are affected by bone loss. Men, too, should be cautious, although the number of men experiencing serious loss is only about one-fifth that of women. The RDA for calcium is1,000 mg. Calcium is especially important for pregnant and breastfeeding women. Research has proven that adequate calcium intake is especially important to preteen girls. Because it is difficult to obtain that amount from food alone, and because some individuals may be allergic to the best dietary sources of calcium, supplementation is recommended. If you do not eat two or three servings of calcium-rich foods daily, a calcium-magnesium supplement containing trace elements is an important consideration.

Nutrition for the Structural System Nowhere is the axiom "teamwork is essential" more obvious than in the skeletal system. Building strong bones calls for coordination of all vitamins and minerals, with special emphasis on the macrominerals calcium, phosphorus and magnesium, followed by the trace elements boron, manganese and copper. However, good bone density also relies on vitamin C and the B vitamins, which are essential to bone/tissue building functions.

The word bone was derived from a Greek word meaning dried up, but bone is anything but dried up. In fact, about one-third of bone's composition is water. Bone is biologically active, and millions of red blood cells are manufactured in the bone marrow, the soft inner core. Internal bone structure is made up of collagen, from Greek words meaning glue-forming. Calcium and mineral salts are deposited there and make bone as tough as reinforced concrete. If the collagen were removed, bones would crumble. If the salts were removed, bone would be as flexible as rubber. The outer structure is a fibrous coating well supplied with nerve endings and blood vessels.

Muscle - A major type of tissue adapted to contract, allowing body movement and mobility.Bone - Serves as a framework for the body and protects its internal organs.Connective Tissue - A kind of tissue that connects, supports or surrounds other tissues and organs.

If you have four or more of the following indications, you may consider nutritional aid to the structural system. Skin/complextion problems Hair loss Sore or painful joints Difficulty in maintaining ideal weight Low endurance/stamina More than 2 cups of caffeinated beverages per day Brittle or easily broken fingernails Muscle cramps Feeling out of control Weak bones, teeth or cartilage Don't get enough exercise

Although an adult's skeleton weighs only a little more than 20 lbs., it is capable of bearing incredible loads. This is largely due to the fact that bones are not only hard, but resilient. In fact, bone tissue is almost 20 times as resilient as steel.